Dear Murali,
Thank you for sharing. This is a wonderful general lecture. Excellent slides. Hope it's OK to use them soemtimes.
Will share mine also for you and others to use.
Best wishes
A Bakhai - London

Heart - anatomy :

Heart - anatomy Has four chambers
Two pumping chambers
Four non return valves
Two valves on either side
Right side pumps through the lungs (pulmonary circulation)
Left side pumps through the entire body (systemic circulation)
Left heart & its valves are more susceptible to damage, since it works against the entire vascular resistance of systemic circulation

Blood vessels :

Blood vessels Arteries carry blood from the heart to various organs
Transfer of oxygen, carbon dioxide and nutrients occur in the capillary network at various organs
Veins collect the blood and returns to the heart for pumping again
Blood flow controlled by the vessel resistances and pressure generated by the heart

Circulatory system - revisited :

Circulatory system - revisited LA and RA are the collection chambers
LV and RV are the pumping chambers
Two valves, at the inlet and outlet of the pumping chambers
Tricuspid valve
Pulmonary valve
Mitral valve
Aortic valve

Working of heart :

Working of heart The natural pacemaker of the heart is the Sinoatrial (SA) node
The electrical impulse leaves the SA node and travels to the right and left atria, causing them to contract together
The electrical impulse subsequently reaches Atrio ventricular Node (AV node) and travels through the Bundle of His where it rapidly spreads using Purkinje Fibers to the muscles of the Right and Left Ventricle, causing them to contract at the same time

Electrical subsystem complications :

Electrical subsystem complications When the natural conduction pathways does not perform correctly, or the natural pacing system fails, the heart does not beat at the appropriate rates
In such cases, implantable pacemakers are used for regulating the cardiac rhythm
Called ventricular resynchronization therapy

Pacemakers :

Pacemakers An electronic circuit senses the ECG and generates signals to resynchronize the heart rhythm.
The heart rhythm is controlled to achieve the required heart rate; depending on the condition of the patient
Provided with a battery (with typical 10 year life) and is totally implantable device

Pacemaker :

Pacemaker Antenna is used for external programming of the pacemaker subsequent to implantation

Septal defects in heart :

Septal defects in heart Atrial septal defect (ASD) relates to a communication between the two atria chambers giving rise to mixing of oxygenated and unoxygenated blood
Ventricular septal defect (VSD) relates to a communication between the two ventricles.
These congenital defects, can lead to growth retardation and in certain patients fatal consequences ASD VSD

Septal defects - management :

Septal defects - management Normally fabric patches made of Polyethylene Terephthalate (PET) and Poly tetra flouroethylene (PTFE) are employed to close these defects
Currently, catheter based closure devices using shape memory alloys are being available to treat this abnormality
The SMA alloys have properties to change its shape based on the temperature of the environment

Catheter based ASD closure devices :

Catheter based ASD closure devices ASD Closure device

Heart valve defects :

Heart valve defects The heart valves, normally due to certain diseases, fail to function as unidirectional check valves; they either become too leaky in the closed state (Regurgitation) or very narrow and offer resistance to blood flow in the open state (Stenosis)
Mostly, rheumatic fever and associated complications cause valvular defects
Many modes of management are feasible for valvular defects – depending on the state of the valve and the patient

Heart valve defects - management :

Heart valve defects - management Corrections : The state of the valve is improved, either using a catheter and balloon or using surgical intervention on valve using annulaoplasty rings
Balloon expansion is employed in the case of stenosis
Annularplasty rings are mostly for valve leaks
Correction procedure cannot be performed in all cases Annularplasty ring

Coronary artery bypass grafting :

Coronary artery bypass grafting Patient’s own mammary artery or saphaneous veins are employed for grafting
Synthetic grafts (tubes) developed till date are not very successful
Researchers around the world are working to develop suitable small diameter synthetic grafts to replace coronary arteries Mammary artery grafting Saphaneous vein grafts

Revascularization :

Revascularization creation of channels in myocardium using Laser beams Laser myocardial revascularization techniques uses laser energy to create new myocardial channels and produce effects which lead to improved myocardial blood supply and reduction in angina.
Revascularization using drugs and capillary promoting agents are also being tried

Plaque removal :

Plaque removal Catheter loaded with a diamond rotary blade
12,000 to 15,000 rpm rotation speed
Debris generated may be collected using a collection system to eliminate the possibility of thrombus formation
Yet, not very popular

PTCA :

PTCA Percutaneous Transluminal Coronary Angioplasty (PTCA), uses a balloon to open a clogged vessel
The PTCA catheter is guided to the required site.
When the balloon is inflated, this presses the plaque against the artery wall and opens up the lumen of the artery to achieve near normal blood flow
Restenosis is the major failure mode

Coronary Stents :

Coronary Stents A type of wire mesh that fits within the artery.
Inserted during the PTCA procedure
When the balloon opens up to press the plaque against the artery wall, the stent opens up, too.
Once the balloon is deflated and pulled out of the artery, the stent stays open and keeps the plaque in place
Bare metal stents
Drug eluting stents

Congestive heart failure :

Congestive heart failure Develops as a result of damage to the heart muscle
Can occur following a heart attack or coronary artery disease
Can also result from strain and pressure placed on the heart following years of untreated heart valve disease or high blood pressure

Intra aortic balloon pumps - IABP :

Intra aortic balloon pumps - IABP IABP uses a balloon mounted on a catheter, which is inserted into the aorta through the femoral artery in the leg
The inflation and deflation of the balloon is synchronized to the heart’s pumping and is controlled from a console
Balloon supports the heart indirectly, augmenting the blood flow

Total artificial heart - TAH :

Total artificial heart - TAH Natural heart is replaced with artificial twin pump
Still in development stage
Used only when
Have end-stage heart failure.
Have a life-expectancy of less than 30 days.
Are not eligible for a natural heart transplant.
Have no other viable treatment options

Cardiopulmonary bypass :

Cardiopulmonary bypass used to support patients during open-heart surgery.
Patients' blood is diverted outside the body through the CPB circuit
This allows for the patient's heart and lungs to bypassed facilitating surgery
CPB machine artificially adds oxygen to the blood and then recirculates the blood back

Extracorporeal cardiac devices :

Oxygenator :

Oxygenator Acts as lung during CPB
Three functions are performed
Adds oxygen and removes excessive carbon dioxide from patients blood
Allows cooling and rewarming of the patient during surgery
Acts as a reservoir of blood to be infused back to the patient as and when required Oxygenator Venous reservoir

Cardioplegia delivery system :

Cardioplegia delivery system Intended deliver cardioplegia solution to the heart to stop its beating during open heart surgery
A cooling coil is provided to cool the solution to around 5C
The solution stops the heart and protects its muscles during the CPB period

Arterial filters & hemo concentrators :

Arterial filters & hemo concentrators Arterial filters are used for removing any blood clots that could have formed in the CPB circuit, prior to infusing back to the patient.
Hemo concentrators are used for removing excess fluid present in the CPB circuit. Employed mainly in pediatric surgical procedures

Cardiovascular devices - Future :

Cardiovascular devices - Future Tissue engineering of cardiovascular devices offer immense opportunity
Research in the area is in primitive stages
One day world may see totally tissue engineered devices working in human heart …… but the day seems far away

Heart :

Heart Typically beats
3000000000
times in person’s life time
Any attempt by man to repair, augment, replace …. are only suboptimal till now and never performs like the one nature created !!